The present invention relates to a new and improved method of, and apparatus for, receiving or taking-over printed products, especially folded printed products, from a revolvingly driven bucket or fan wheel of a printing machine, typically a printing press.
Generally speaking, the method for receiving printed products, especially folded printed products, from a revolvingly driven or rotary bucket or fan wheel of a printing machine, entails fixedly retaining or holding each of the printed products at an edge thereof during their departure out of the compartments or buckets of a rotary bucket or fan wheel and outfeeding such printed products in a shingled or imbricated superimposed product formation.
The apparatus for receiving or taking over printed products, especially folded printed products, from a revolvingly driven or rotary bucket or fan wheel of a printing machine, comprises a conveyor device which is equipped with grippers for the retention of an edge of each associated printed product during their departure or emergence out of the compartments or buckets of the rotary bucket or fan wheel.
It is well known in this technology to insert or stuff into the compartments or buckets of a rotary bucket or fan wheel the printed products departing from the folding apparatus of printing machines. The printed products are hen removed from these compartments or buckets and placed in a shingled array or imbricated product formation upon distributor belts or bands. For the subsequent processing of the printed products, it is of importance that the imbrication spacing or pitch of the printed products is uniform or regular within the laid-out or distributed imbricated product formation.
In order to attain this objective it has already been proposed in Swiss patent No. 626,830, granted Dec. 15, 1981, to engage the printed products at their edges bearing against the floor or base of the compartments or buckets of the rotary bucket or fan wheel before the products depart out of such compartments or buckets. The engagement of such product edges is accomplished by controlled grippers which act upon the leading edges of the products. The printed products which are fixedly retained by the grippers are withdrawn from the compartments or buckets of the rotary bucket or fan wheel and deposited in a shingled array or imbricated product formation upon an outfeeder or delivery conveyor. To ensure that the edges of the printed products which are to be engaged by the grippers positively come to lie within the confines of the grippers, the circumferential velocity of the grippers is smaller than the circumferential velocity of the floor or base of the compartments or buckets of the rotary bucket or fan wheel. Thus, the grippers also assume the role of a conventionally present stripper element, such as a belt, wheel or the like, at which the printed products impact with their leading edges and in this manner can be displaced out of the rotary bucket or fan wheel.
The printed products which are fixedly retained-by the grippers, during sliding out of the rotary bucket or fan wheel, remain in that position which they assumed at the point in time of reception by the grippers in the associated compartment or bucket of the rotary bucket or fan wheel. Nonetheless irregularities in the imbrication spacing or pitch of the shingled or imbricated product formation can arise if the printed products, at the moment of time of engagement by the grippers, do not correctly bear at the floor or base of the associated compartment or bucket. Additionally, during transfer of the printed products from the grippers to the outfeeder or delivery conveyor arranged therebelow there can arise positional displacement or shifting between successive printed products. This can result in irregularities in the imbrication spacing or pitch of the shingled or imbricated product formation.
Furthermore, from the European Published patent application No. 0,179,992, published May 7, 1986, it is known to fixedly clamp printed products infed from above or overhead approximately tangentially to a rotary bucket or fan wheel, at the leading product edges between the walls of the compartments or buckets of the rotary bucket or fan wheel and a revolving belt. In this way it is possible to fixedly retain the printed products during the rotational movement of the rotary bucket or fan wheel. At the lowest point the leading edges of the printed products are then again released and these printed products are allowed to drop onto a conveyor belt in order to form a product stack. Also this prior art solution is afflicted with the drawback that a regular or uniform imbrication spacing or pitch cannot be realized when the printed products are unable to completely drop down into contact with the floor or base of the compartments or buckets of the rotary bucket or fan wheel before they are fixedly retained in place. However, with this prior art equipment such is not of any particular significance when it is recalled, as explained above, that the printed products are placed into stacks and are not further processed in a shingled or imbricated product formation or array.
Furthermore, from U.S. Pat. No. 4,565,363, granted Jan. 21, 1986, it is known to place the leading edges of printed products located in the compartments or buckets of a rotary bucket or fan wheel, during the rotational movement of such rotary bucket or fan wheel, into contact or impacting relationship with cams or stops or the like which are revolvingly driven at a lower velocity in relation to the velocity of movement of the printed products. The printed products ejected by the cams or stops out of the compartments or buckets of the rotary bucket or fan wheel are deposited in a shingled array or imbricated product formation upon a conveyor belt. Due to the impact of the printed products against the cams or stops these printed products are indeed aligned, however during the free fall of the printed products onto the conveyor belt and upon impingement of the printed products at the conveyor belt the printed products can shift in their mutual position and this, in turn, can lead to irregular imbrication spacings or pitches.
In the apparatus disclosed in German patent No. 3,123,406, published Dec. 12, 1985, corresponding to European Published patent application No. 0,067,399, published Dec. 22, 1982 and U.S. Pat. No. 4,487,408, granted Dec. 11, 1984, the printed products are likewise aligned by revolvingly driven cams or dogs which, however, engage at the rear trailing edges of the printed products as soon as these printed products are completely released from the rotary bucket or fan wheel. At the point of time of engagement of the cams or dogs at the rear edges of the printed products the latter, at the region of the leading edges thereof, already are located upon the preceding printed product which is entrained by the distributor belt. Due to the frictional forces prevailing between the products which mutually bear upon one another the cams or dogs can only change to a limited extent the engaged printed product as concerns its position. This means that considerable irregularities in the imbrication spacing or pitch cannot be completely compensated. Such irregularities can arise, for instance, when the printed products do not come to lie in the correct position in the compartments or buckets of the rotary bucket or fan wheel or if the printed products experience a positional change or spatial shift during the free fall of such printed products out of the compartments or buckets onto the distributor belt.